I have a XP SP3 machine with an ASUS P5AD2 Deluxe, P4(R) 3.4GHz socket 775 processor with stock heatseak and fan and 2GB PC2-4200 DDR2 533MHz memory and (2) 250GB WD SATA hard disks. acpi bios revision 1007, (not been updated) This may be overkill, just want to provide as many clues as possible.

The machine has been running for years without problems. Over the years, occasionally it would not boot with "reboot and select proper boot device or insert boot in selected boot device". I would go into the BIOS>IDE configuration and see it set to configure SATA as AHCI. I would change it back to RAID and reboot without problems. Rarer still, it would not boot with "overclocking failed, enter setup to reconfigure system". When I did, SATA was configed as AHCI, change it back to RAID and reboot without problems. If I remember correctly, at these times, in setup it didnt see the boot drive - as is the case now.

primary IDE master - DVD drive
primary IDE slave - not detected

The current problem started a couple days ago - I was getting multiple stop errors:

I tried:
unplugged all USB devices
boot into Windows normally, wouldnt last more than a minute before it rebooted it self
last known good config
in safe mode long enough before it reboots, 2 items in msconfig/startup without names, just squares.
in safe mode unchecked all in msconfig/startup and checked normal startup
after one of these reboots it ran chkdsk which removed 1 or 2 things I dont remember, otherwise good report
in safe mode did a system restore
reseated memory after using a pencil eraser on contacts
held power button in while I unplugged it from AC power
normal POST beeps

I tested the memory with GoldMemory, two tests, a quick test and a thorough test. All failed I stopped it 5 hours into the thorough test with 1,094,579 errors, 3.5 hours into a quick test with 732,995 errors. I tried it with a known good 1GB stick of DDR2 PC2-5300 from another machine - NG.

Intel Application Accelerator RAID option ROM v4.5.0.6448. The Matrix RAID is configured as RAID 0 for the system files and RAID 1 for the data. Before loading OS, the physical drives are listed and the status of the Matrix RAID drives are displayed. Initially the RAID 0 system drive showed as failed/not bootable and the RAID 1 data drive showed as degraded. When I got into the BIOS one of the physical drive was gone. Started the machine again, the physical drives were listed and the RAID 0 system drive showed as failed/not bootable and the RAID 1 data drive showed as rebuild/bootable. What?

Now as I am writing this and rebooting to go back into setup, del will not get into setup and it gives the 'no boot media' error msg. I restart it, and it shuts itself down. I held power button in while I unplugged it from AC power and I was able to get to the BIOS on the next try.

0x0000008E usually points to a RAM issue, but those P5 boards from ASUS where awfully flaky... It is worthwhile though to check for bulging/leaking capacitors on the motherboard (unusual with that one), the graphics card and the PSU (what you can see - Antec is a good branded PSU)...

I have been programming on computers since the ZX81.
I am an apprentice trained Electronics Engineer with qualifications to back it up.
I have been repairing computers since 1996.
Yet to some people I still know nothing...

Thanks for the reply Mr T. I see no capacitors on the main board or the video card that look other than they should. I cant see any in the PSU. The hardware monitor in the BIOS shows the Antec's fan turning at only 937 RPM.

I have been programming on computers since the ZX81.
I am an apprentice trained Electronics Engineer with qualifications to back it up.
I have been repairing computers since 1996.
Yet to some people I still know nothing...

Download and burn to a CD Ubuntu... The Ubuntu website tells you how... Detach your hard drive and run the CD as a live CD - if this fails to work, you have a hardware fault in the motherboard...

I have been programming on computers since the ZX81.
I am an apprentice trained Electronics Engineer with qualifications to back it up.
I have been repairing computers since 1996.
Yet to some people I still know nothing...

Do a voltage check with a digital multimeter, at the power plug of the mobo. If all voltages are within +/- 2%, there should be no problems. But if main rails show greater differential, then suspect the PSU. The -12 volt source can be off by up to 3 volts, and still be good.
Yes, a PSU can suffer the 'bad caps' syndrome. Have had several. Be especially cautious if opening a PSU, as there can be 200 volts DC or higher on the primary capacitors.. posing a nasty shock hazard! First pull the AC cord, then attempt a few starts to drain energy from the main caps. That should drop them to below 30 volts, safer to work around.
Likely the reason for a low fan speed is that the PSU has not gotten hot enough to lower the thermistor resistance in the fan circuit, which would speed up the fan.

Mr T wrote:0x0000008E usually points to a RAM issue, but those P5 boards from ASUS where awfully flaky... It is worthwhile though to check for bulging/leaking capacitors on the motherboard (unusual with that one), the graphics card and the PSU (what you can see - Antec is a good branded PSU)...

Whats the consensus, replace board or PSU? I guess that depends on if the power is fried and if thats the case I suppose its a possibility that it fried the board and I will have to end up replacing both, right?. Bummer.